81748281789 has 6 divisors (see below), whose sum is σ = 118080851486. Its totient is φ = 54498854520.

The previous prime is 81748281781. The next prime is 81748281799. The reversal of 81748281789 is 98718284718.

81748281789 is a `hidden beast` number, since 8 + 1 + 7 + 482 + 81 + 78 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 68373359289 + 13374922500 = 261483^2 + 115650^2 .

It is not a de Polignac number, because 81748281789 - 2³ = 81748281781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81748281781) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4541571202 + ... + 4541571219.

Almost surely, 2^81748281789 is an apocalyptic number.

It is an amenable number.

81748281789 is a deficient number, since it is larger than the sum of its proper divisors (36332569697).

81748281789 is a wasteful number, since it uses less digits than its factorization.

81748281789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9083142427 (or 9083142424 counting only the distinct ones).

The product of its digits is 14450688, while the sum is 63.

The spelling of 81748281789 in words is "eighty-one billion, seven hundred forty-eight million, two hundred eighty-one thousand, seven hundred eighty-nine".